Interlocking electromagnetic relay



Nov. 16, 1954 KEEN INTERLOCKING ELECTROMAGNETIC RELAY Filed March 29, 1951 m \Wli. \\l/ 5.: KIIL PI IIIIIIL 0 L Inventor Ila/vow 190m k- United States Patent Ofitice 2,694,758 Patented Nov. 16, 1954 INTERLOCKING ELECTROMAGNETIC RELAY Harold Hall Keen, Letchworth, England, assignor to British Tabulating Machine Company Limited, London, England, a British company Application March 29, 1951, Serial No. 218,119

Claims priority, application Great Britain January 12, 1951 8 Claims. (Cl. 20098) This invention relates to electromagnetic relays of the double acting type.

When it is required to maintain a set of relay contacts closed for a considerable period, it is frequently convenient to provide mechanical locking for the armature so that current is not required to maintain the relay operated, but only to effect setting. It is known for this purpose to employ a relay in which the armature is held in unoperated position directly by the spring pressure of the contacts. When the operating coil is energized, the armature is attracted, closing the contacts, and the armature is then held in this position by a mechanical latch, allowing the operating coil to be de-energized. The mechanical latch is released by energization of a second or unlatching coil.

This type of construction provides positive locking of the armature in only one position and the parts required for the operating coil and armature and the unlatching coil and armature are dissimilar.

An object of the present invention is to provide an improved electromagnetic relay of the double acting type, in which the armature is positively mechanically held in both operative positions by the action of two levers which also each operate a set of contacts.

A further object of the invention is to provide a double acting relay in which the two coils and their associated parts are of similar form.

The invention will now be described by way of example with reference to the accompanying drawings, in which:

Figure 1 is a plan view of the top of the relay.

Figure 2 is a plan View of the underneath of the relay.

Figure 3 is a rear elevation of the relay with certain parts removed.

Figure 4 is a side elevation of the relay.

The relay is intended to be plugged in as opposed to being permanently wired in circuit, thus facilitating maintenance and replacement of the relay. To this end, the parts of the relay are mounted on a flat plate, which is provided with a set of connection strips.

The mounting plate is built up from two paxolin plates 1 and 2 (Figures 1, 2 and 3). Between the plates at either side are two brass strips 3 and 4. These strips have portions 5, 6, 7 and 8 at either end, which project outside the paxolin to form guiding keys which locate the relay when it is inserted into a suitable mounting frame.

In between the plates in the central portion is a brass strip 9 (Figures 2 and 3). This strip is flush with the top edge of the plates 1 and 2 (Figure 2) but does not extend to the lower edge. In the gap between the bottom edge of plate 9 and the plates 1 and 2 are placed six connection strips 10. One end of these project beyond the edges of the mounting plate sufficiently to engage contact members when the relay is inserted in its frame and the other ends are bent at right angles to project through holes in plate 1 to form soldering lugs 11 (Figure 1).

Also between the plates 1 and 2 are two further connection strips 12 and 14 (Figures 1 and 2). These extend at their outer ends to the same distance as the strips and are located in the space between strips 3 and 9, and 4 and 9 respectively (Figure 2). The inner ends of strips 12 and 14 are bent at right angles to form brackets 13 and 15 respectively, which each project through holes in plate 1 and form a support for a set of contact blades.

The two plates 1 and 2 and the various brass strips between them are bonded together to form an integral unit by means of a suitable adhesive applied under pressure. It would also be possible to produce the same integral unit by a moulding process.

A hole is provided through plates 1 and 2 and the lower part of plate 9. In this hole is secured a post 16 carrying a shouldered nut 17 on the lower end (Figures 1 and 2). The shoulder on nut 17 forms a pivot for the lower ends, which are reduced in thickness, of two right angled levers 18 and 19 (Figures 2 and 3). The upper ends of these levers are secured by screws 60 near the upper edge of the plates 1 and 2, the screws passing through slots in the plates and strip 9.

The upper end of post 16 forms the mounting for an armature 20, one end of which is formed into a U-section but at an angle to the main part of the armature. The post 16 passes through holes in the limbs of the U-section and the armature is retained in position by a spring washer 21 (Figure l).

The other end of armature is formed into a V shape, such that it engages with either of two notches formed in two levers 22, 23 (Figures 1 and 3). Notch 24 in lever 22 is shown in Figure 1, the armature being engaged with the similar notch in lever 23.

Lever 22 is bent at right-angles in the plane of plate 1 and is pivoted on a screw 25 secured in a rod 26 which is in turn secured to the lever 19 (Figures 1, 3 and 4). Clearance holes 70, 71 are provided in plates 1 and 2 respectively to allow rod 26 a certain freedom of movement when plate 19 is adjusted, as will be described later.

The arm of lever 22 remote from the armature 20, and which overlies the left hand side of plate 1 (Figure 1) has two small angle bends in it (Figure 4), so that the end section is parallel to the part pivoted on rod 26, but at a slightly greater distance from plate 1. At the end of this section is a projection 28 (Figure l), in the plane of plate 1. The end of this projection is bent at right angles to the plane of plate 1 to form a stop 29 which engages the contact set secured to the bracket 15.

The contact set comprises a rigid brass stop member 30, a spring contact member 31, a second rigid stop 34, an insulating spacer 35, a second spring contact 32, a flexible insulating strip 33, a second insulating spacer 36, and a steel block 37 (Figure l). The parts are assembled in this order and fixed to the bracket 13 by two screws 38. The spring contact 31 is in contact with the stop 30, which in turn is in contact with bracket 15, hence this contact 31 is electrically connected to the connection strip 14 of which bracket 15 forms a part.

The spring contact 32 is insulated from bracket 15 by the spacers 35 and 36 and from the stop 29 on lever 22 by the flexible strip 33. Contact 32 is connected by a wire (not shown) to a lug 11 of one of the connection strips It When the end of armature 29 engages notch 24 in lever 22, the lever is allowed to move clockwise about the pivot screw 25 under the pressure of spring contact 32 on extension 29, thus opening the contacts 31 and 32. If the armature is now moved out of notch 24, the end of the armature engaging the edge of lever 22 will force the lever to move anti-clockwise, so that extension 29 will contact 32 against the spring tension to close contacts 31 and 32.

To guide the lever 22, the edge of the projection 28 engages in a slot cut in red 27 (Figures 1 and 4), which is secured to part 8 of the strip 4. As a further guide, the end of lever 22 at 39 adjacent the armature 20 is bent downwards at an angle of approximately 45 so that it bears lightly on the upper surface of lever 23.

The lever 23 is exactly the same in form as lever 22, and is mounted and guided in a similar manner. The arm of lever 23 remote from the armature 2t) overlies the right hand side of plate 1, so that the lever is reversed compared with lever 22, that is, the upper surface of one lever corresponds to the lower surface of the other. The height of rod 40 (Figure 3) which carries the pivot for lever 23 and guide rod 41 is such that the end of lever 23 adjacent the armature 20 lies underneath the corresponding end of lever 22. Parts relating to lever 23 which correspond with those relating to lever 22 are given similar reference numbers with the suffix a.

The ends of the levers 22 and 23 in contact with armature 20 are positioned by a cylindrical block 42 secured to the brass strip 9 (Figures 1, 2 and 3). This block is slotted vertically to provide clearance for the armature 20 and is slotted horizontally to provide locating surfaces for the two levers 22 and 23 (Figures 1 and 3 Two electromagnets are mounted adjacent to the armature 20, one electromagnet on either side of the armature. The left hand electromagnet (Figure 1) comprises two windings 43 mounted on two pole pieces 45. These pole pieces are secured to the centre limb of a U-shaped yoke 47 which has a bracket 49 with slotted holes therein, on the two outer limbs so that the electromagnet assembly may be secured to the lever 19 by screws 50. Clearance holes in the plate 1 and strip 9 allow the assembly to move when lever 19 is adjusted.

The right hand electromagnet is constructed similarly and comprises coils 44, pole pieces 46 and yoke 48, the assembly being secured by screws 51 to the lever 18.

When the right hand electromagnet is energized, the armature 20 is moved clockwise about the pivot 16 (Figure 1), so that lever 23 is permitted to move anti-clockwise about the pivot screw 25a and the notch in lever 23 to drop onto the V-shaped end of armature 20. Thus the extension 29a of lever 23 moves away from the fixed stop 30a, allowing the contacts 31a and 32a to open. At the same time, lever 22 is also moved anti-clockwise as the armature 20 comes off the notch 24 in the lever. This movement presses extension 29 of the lever against the insulating strip 33, thereby closing the contacts 31 and 32. The relay then assumes the position shown in Figure 1.

When the left hand electromagnet is energized, the armature is moved anti-clockwise, so that the end of the armature is located in the slot in lever 22. In consequence, the movement of the levers 22 and 23 is the reverse of that described above so that contacts 31 and 32 open and contacts 31a and 32a close.

In either position, the armature is mechanically locked by the engagement of the end of the armature with the notch in one or other of the levers 22 and 23. The spring tension of the contacts 32 and 32a urges the lower ends of the levers 22 and 23 outwards, so that, pivoting on the screws 25 and 25a, the levers are always biassed in such a way as to maintain their other ends in contact with the armature 20, ensuring that the armature is engaged with the notch in one lever or the other.

Connections (not shown) are made from the electromagnet coils 43, 44 and-from contacts 32, 32a to the soldering lugs 11.

The electromagnets and the levers 22 and 23 are secured to the levers 18 and 19 which pivot about the post 16, which also forms the pivot for the armature 20. This method of construction provides a simple method of adjusting the relay for optimum operation. Firstly, the armature 20 is centralised by inserting spacers between the armature and each side of the vertical slot in the block 42.

The screws 50 and 51 securing the electromagnets are loosened and the electromagnets are moved away from the armature. They are temporarily locked in this position by tightening screws 50 and 51, and screws 60 are loosened. This allows levers 18 and 19 to be pivoted about the post 16 and by gently pushing the upper ends of the levers 22 and 23, the notches in both levers are engaged with the end of the armature. Thus the two sets of levers are centralised with respect to the armature. The screws 60 are then tightened to hold the levers 18 and 19 in this position.

The screws 50 and 51 are again loosened, the electromagnets are adjusted to provide a suitable gap between the armature and the respective pole pieces, and they are then locked in this position by screws 50 and 51. Finally, screws 60 are loosened and levers 18 and 19 are adjusted until the position of levers 22 and 23 is such as to ensure correct operation of the contacts and the required travel of armature 20. Screws 60 are then tightened to hold the parts in the correctly adjusted position.

What I claim is:

1. A double-acting electromagnetic relay comprising an armature freely pivotable between a first and a second extreme position, an electromagnet disposed on each side of said armature, two freely pivoted levers, each having a notch therein, the end of said armature being received in and positively held against accidental dislodgement by the notch of one said lever at one extreme position and by the notch of the other said lever at the other said extreme position, spring means for biasing said levers into engagement with said armature, each lever being pivoted against its bias on movement of said armature out of the notch in that lever and into the notch of the other lever on energisation of said electromagnets and a set of contacts for each said arm operatively engaged by the associated lever but electrically insulated therefrom, each set of contacts being mutually engaged and disengaged on opposite pivotal movements of the associated lever.

2. A double-acting electromagnetic relay comprising an armature freely pivotable between a first and a second extreme position, an electromagnet disposed on each side of said armature, two levers freely pivoted intermediate the ends thereof, each lever having a notch therein near one end thereof, the end of said armature being received in and positively held against accidental dislodgement by the notch of one said lever at one extreme position and by the notch of the other said lever at the other said extreme position, spring means for biasing said levers into engagement with said armature, each said lever being pivoted against its bias on movement of said armature out of the notch in that lever and into the notch of the other lever on energisation of said electromagnets and a set of contacts for each said lever operatively engaged by but electrically insulated from the other end of the associated lever, each set of contacts being mutually engaged and disengaged on oppositive pivotal movements of the associated lever.

3. A double-acting electromagnetic relay comprising an armature freely pivotable between a first and a second extreme position, an electromagnet disposed on each side of said armature, two freely pivoted levers, each lever having a notch therein, the end of said armature being received in and positively held against accidental dislodgement by the notch of one said lever at one extreme position and by the notch of the other said lever at the other said extreme position, and a set of spring contacts for each said lever operatively engaging against and electrically insulated from the associated lever and biasing said lever into engagement with said armature, each said lever being pivoted against its bias on movement of said armature out of said notch therein and into the notch of the other lever by energisation of said electromagnets and each said set of contacts being mutually engaged imd disengaged on opposite movements of the associated ever.

' 4. A double-acting electromagnetic relay comprising an armature having a V-shaped end and freely pivotable between a first and a second extreme position, an electromagnet disposed on either side of said armature, two freely pivoted levers, each said lever having a notch therein, said V-shaped end being received in and nositively held against accidental dislodgement by the notch of one said lever at one extreme position and by the notch of the other said lever at the other said extreme position, spring means for biasing each said lever into engagement with said V-shaped end of s id armature, each said lever being pivoted against its bias on movement of said armature out of said notch therein and into the notch ofthe other said lever, and a set of ontacts for each said lever operatively engaging against and electrically insulated from said lever, the distance between the pivot axis of each said lever and the notch therein being less than the distance between said pivot axis and the point of engagement of said contacts with said lever.

5. A double-acting electromagnetic relay comprising an armature having a V-shaped end and freely pivotable between a first and a second extreme position, an electromagnet disposed on either side of said armature, two levers freely pivoted intermediate the ends thereof each said lever having a notch near one end thereof, said V-shaped end of said armature being received in and positively held against accidental dislodgement by the notch of one said lever at one extreme position and by the notch of the other said lever at the other said extreme position, and a set of spring contacts for each said lever operatively engaging but electrically insulated from the other end of the associated lever and biasing said lever into engagement with said V-shaped end of said lever, each said lever being pivoted against its bias to bring the contacts of the associated set into mutual engagement on movement of said armature out of the notch therein and into the notch of the other said lever on energisation of one of said electromagnets and the distance between the pivot axis of said lever and the notch therein being less than the distance between said pivot axis and the point of engagement of said contacts with said lever.

6. A double-acting electromagnetic relay comprising an armature pivoted near one end about a pivot axis and having the other end V-shaped, two carrying members, each pivoted about said pivot axis, two electromagnets disposed one at each side of said armature and adjustably mounted separately on said members, two levers freely pivoted one on each of said members, each said lever having a notch therein, said V-shaped end of said armature being received in and positively held against accidental dislodgement by the notch of one said lever, in one extreme pivotal position of said armature and by the notch in the other said lever in another extreme pivotal position of said armature, and a set of spring contacts for each said lever operatively engaging but electrically insulated from the associated lever and biasing said lever into engagement with said V-shaped end of said lever, each said lever being pivoted against its bias to bring the contacts of the associated set out of mutual engagement on movement of said armature out of the notch therein and into the notch of the other said lever on energisation of one of said electromagnets.

7. A double-acting electromagnetic relay comprising two spaced and opposed electromagnetic means, a single armature means disposed freely pivotal between said two electromagnetic means, two levers mounted freely pivotal, each of said levers being notched at its end situated adjacent to one end of the armature means, the said end of the armature means being V-shaped and engageable with said lever notches, and two sets of spring contacts, the other end of each of said levers having means coacting with the respective one of said sets of spring contacts, the said spring contacts biasing the levers into coaction with the armature means, engagement of the said V-shaped end of the armature means with either one of said lever notches retaining the armature means in the respective one of two positions solely under the bias of the respective set of spring contacts, and energization of one of said electromagnetic means moving the armature means into engagement with the notch of the respective lever whereby the armature means is movable from one position into the other upon energization of the respective electromagnetic means.

8. A relay as defined in claim 7, in combination with a pair of members each supporting one of the electromagnetic means and the lever coacting therewith, the said members being pivotal about the same center as the armature means.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 139,302 dlnfreville May 27, 1873 289,137 Putnam Nov. 27, 1883 621,739 Baumann Mar. 21, 1899 811,996 Barclay Feb. 6, 1906 1,422,625 Schwartz July 11, 1922 1,497,300 Minton June 10, 1924 1,550,611 Howe Aug. 18, 1925 1,946,717 Snyder Feb; 13, 1934 2,068,682 Keefe Jan. 26, 1937 2,169,141 Gille Aug. 8, 1939 2,421,641 Obszarny June 3, 1947 FOREIGN PATENTS Number Country Date 516,696 Great Britain Jan. 9, 1940 

